Amanda Knox has made a courtroom appeal against her conviction for the murder of UK student Meredith Kercher, saying she was "paying with her life".
The US student told a jury in Perugia: "I did not kill, I did not rape, I did not steal. I was not there."
Her ex-boyfriend Raffaele Sollecito earlier denied accusing Knox of the murder and said he was in a "nightmare" he had never woken up from.
Miss Kercher's sister said it would be "difficult to forgive anything".
Stephanie Kercher was speaking at a news conference in Perugia ahead of the verdict, which is expected on Monday evening.
"It is very difficult to understand what happened that night without knowing the truth," she told reporters.
Earlier Knox, 24, who was sentenced to 26 years in jail in 2009, told a packed courtroom she had been betrayed and manipulated.
Tearful, and speaking in fluent Italian, she said: "I am not who they say I am. The perversion, the violence, the lack of respect for life - I did not do the things they are saying I did."
Knox had been working on her speech for three months, her father told BBC correspondent Luisa Baldini.
Raffaele Sollecito, 27, who was given a 25-year term, told the jury he had never harmed anyone in his life and the claims against him were "totally untrue".
"I've heard that I have accused Amanda, this is not true, this is totally untrue," he said.
His lawyer Giulia Bongiorno told reporters his client was "very emotional" but "strong" and sure of his innocence.
"We do say there have been an awful lot of mistakes, mainly not asking for an expert opinion," she said.
"The way things were personalised was something I didn't particularly like."
The pair have since been taken back to jail while the jury considers its verdict.
Prosecutors have said they will appeal if the verdict is overturned.
Much of the case has centred on a review of DNA evidence on a knife, thought to be the murder weapon, which indicated that the evidence could be flawed.
The defence team has also challenged witness sightings of Knox and Sollecito near the murder scene.
But prosecutors have called for the sentences to be increased to life terms, saying there is also considerable circumstantial evidence putting the ex-lovers at the scene of the killing.
Knox told the jury: "I had good relationships with everybody who was living in my flat. I was untidy, careless, but we did have good relationships.
"I shared my life, particularly with Meredith. She was always very kind towards me. Meredith was killed and I have always wanted justice for her. I do not run away from the truth and I've never run away from it."
She added: "I want to go back home. I want to go back to my life. I don't want to be punished. I don't want my life and my future to be taken away for something I didn't do because I am innocent."
Francesco Maresca, the Kercher family lawyer, said it was a tense, emotional time for them as the verdict neared.
He said the Kerchers had followed the appeal closely, and thought the legal process had been "thorough".
"The Kerchers are fully satisfied with what has been done by the judges," he said.
The trial has heard some colourful phrases used to describe Knox, with one lawyer comparing the American to Who Framed Roger Rabbit cartoon character Jessica Rabbit, and another to a witch.
Carlo Pacelli, who represents Diya "Patrick" Lumumba - the man Knox originally accused of the murder - said she had a split personality.
One side was "angelic, good, compassionate, and in some ways even saintly", but the other side was "Lucifer-like, demonic, satanic, diabolic" and "longs to live out borderline extreme behaviour", he said.
Knox's family have said they will take her back to Seattle immediately if her conviction is overturned, despite prosecutors vowing to appeal.
Andrea Vogt, a freelance journalist for the Seattle Post, said a big party was already under way in Knox's home city.
People had gathered to hold a vigil and erupted in applause after Knox's speech to the appeals court, she added.
If she is freed, the reception to Knox's return would be "overwhelmingly positive" in Seattle. But if her conviction was upheld, there would be "an outcry from the US", she added.
Miss Kercher, from Coulsdon, south London, had been sharing a cottage in Perugia with Knox during a year abroad from Leeds University.
Prosecutors say she was killed in a brutal sex game which went wrong. Her throat had been slit and she had been sexually assaulted.
Miss Kercher's family have said they feel the true victim has been "completely forgotten", with the media's focus on Knox.
Our correspondent said Miss Kercher's family had now arrived in Perugia. A representative from the British Consulate in Rome had also arrived to offer any help should they need it, she said.
A third person - Rudy Guede, 24 - was also convicted of Miss Kercher's murder in a separate trial and was sentenced to 30 years in prison.
His conviction was upheld on appeal but his sentence reduced to 16 years.